i am running ls injectors from another engine. but, they are still used. i checked the resistance and they were all good and i visually inspected them...i dont know what else i myself can do. i have been thinking the exact same thing you are...vaccum leak. all the signs point to it. but, i cannot find one if that is the case. i am beginning to think that the throttle position, map or iac valve might be the problem because i dont have a pump to check the map, and because someone gave me the throttle body. im not real confident in the iac valve either because. im running a type r intake manifold with an ls tb and iac. i know its not the perfect setup but, i just didnt think it would cause the engine not to run... its so frustrating because the engine fires up like i just drove it off the lot but, it can only stumble briefly then stall. i think i am going to try a leak down test because i am running the 95 head w/ 97 parts with the exception of the valvetrain and i dont know the condition of the components. it pumped out 200 give or take a couple psi in all cylinders but i still dont know if it is maintaining that pressure or leaking out somewhere. anyways, dont give up on me. your about the only source of support i have left and i really appreciate it!